Home  |  News  |  Events  |  Contact  |  Publications  |  City of Cambridge


West Nile Virus Found in Cambridge Mosquitoes

Risk level raised to "moderate" in Cambridge

July 17, 2017

State health officials reported on July 13 that a mosquito sample in Cambridge tested positive for West Nile virus. The mosquito sample was collected from a trap in West Cambridge.

Positive mosquito samples have also been detected locally in Belmont and Boston.

On July 17, the Massachusetts Department of Public Health raised the risk of West Nile virus infection from “low” to "moderate" in Boston, Belmont, Brookline, Cambridge, Newton, and Watertown.

“We are advising residents to start taking precautions to avoid mosquito bites, such as wearing repellent or protective clothing in the evening, fixing screens, and eliminating standing water on their property,” said Claude Jacob, the city’s Chief Public Health Officer and director of the Cambridge Public Health Department.

The virus is usually transmitted to humans through the bite of an infected mosquito. Most human West Nile virus infections are mild, but a small number of people become very sick. People over 50 are at greatest risk for serious illness, especially those with weakened immune systems.

In 2016, there were 16 human cases acquired in Massachusetts.

The East Middlesex Mosquito Control Project is currently in the process of treating the city’s storm drains with larvicide, which kills mosquito larvae before they can grow to adulthood. 
The best way to avoid West Nile virus is to prevent mosquito bites.  Some tips:
  • Apply insect repellent when outdoors. Use a repellent with DEET, permethrin, picaridin, oil of lemon eucalyptus or IR3535. DEET products should not be used on infants under two months of age and should be used in concentrations of 30% or less on older children. Oil of lemon eucalyptus should not be used on children under three years of age. Follow the directions on the package.
  • Be aware of peak mosquito hours. The hours from dusk to dawn are peak biting times for many mosquitoes. Consider rescheduling outdoor activities that occur during evening or early morning.
  • Clothing can help reduce mosquito bites. Wearing long-sleeves, long pants, and socks when outdoors will help keep mosquitoes away from your skin.
  • Get rid of mosquito breeding sites in your yard. Mosquitoes lay their eggs in still water. Empty standing water from flower pots, buckets, barrels, and children’s pools. Change the water in pet dishes and replace the water in bird baths weekly. Drill holes in tire swings so water drains out.
  • Make sure that window and door screens fit tightly and are in good condition.
State and county information about West Nile virus and reports of West Nile virus activity in Massachusetts can be found on the state health department website at: www.mass.gov/dph/mosquito and http://www.mosquitoresults.com.

For local West Nile virus updates, call the Cambridge Public Health Department at 617-665-3838 or visit http://www.cambridgepublichealth.org/services/environmental-health/mosquito-borne-diseases/west-nile-virus.php.

Suzy Feinberg, MPH
Public Information Officer

Show releases from: